Isolation and characterization of the active product of B. pertussis which induces lymphocytosis is being pursued. The interaction between lymphocytosis-promoting factor (LPF) and lymphoid cells is being examined with respect to receptor-sites, kinetics and effect on cell function. The effects of LPF on cyclic nucleotide metabolism will be subjected to further study. The nature of the adjuvant principle of B. pertussis is to be determined. Fractions of culture supernatant fluids as well as extracts from whole organisms, including endotoxin, will be tested for their ability to act as adjuvants. In addition, the fractions will be tested for their ability to induce protection.